Physiology of Digestion Dr Mahesha H B Associate
Physiology of Digestion Dr. Mahesha H B Associate Professor Department of Sericulture Yuvaraja’s College, University of Mysore, India 10 March 2021 www. hbmahesh. weebly. com 1
Physiology: The branch of biology that deals with the normal functions of living organisms and their parts. or The way in which a living organism or bodily part functions. Digestion: The process of digesting food 10 March 2021 www. hbmahesh. weebly. com 2
Anatomy of silkworm larva 10 March 2021 www. hbmahesh. weebly. com 3
10 March 2021 www. hbmahesh. weebly. com 4
Alimentary Canal - three layers Inner Tunica Intima Middle Epithelial Outer Muscular In case of midgut, peritrophic membrane is the innermost layer which protects from the mechanical damage 10 March 2021 www. hbmahesh. weebly. com 5
Fore Gut Pharynx Cardiac Valve Oral Operture A pair of Salivary Glands and Salivary Reservoirs usually reside in the thorax (adjacent to the foregut). Salivary Ducts lead from the glands to the reservoirs and then forward, through the head, to an opening (the Salivarium) behind the hypopharynx. Movements of the mouthparts help mix saliva (contains amylase) with food in the buccal cavity. 10 March 2021 www. hbmahesh. weebly. com 6
Mid Gut • Digestion and Absorption • Goblet Cells at midgut Epithelium Secretes digestive Fluid • Cylindrical cells –Absorption • Hindgut • Small Intestine, Colon and Rectum. Pylorus Valve • 10 March 2021 www. hbmahesh. weebly. com 7
Diagrammatic representation of typical insect midgut cells: (A) columnar cell with plasma membrane infoldings arranged in long and narrow channels, usually occurring in fluid-absorbing tissues; (B) lepidopteran long-necked goblet cell; (C) columnar cell with highly developed basal plasma membrane infoldings displaying few openings into the underlying space, usually occurring in fluidabsorbing tissue; (D) cyclorrhaphan dipteran oxyntic (cuprophilic) cell; (E) lepidopteran stalked goblet cell; (F) columnar cell with highly developed plasma membrane infoldings with numerous openings into the underlying space, frequently present in fluid-secreting tissue; (G) regenerative cell; (H) hemipteran midgut cell; (I) endocrine cell. Note particles (portasomes) studding the cytoplasmic side of the apical membranes in B, D, and E and of the basal plasma membranes in A. Abbreviations: Bl, basal plasma membrane infoldings; M, micro-villi; Mi, mitochondria; MM, modified microvilli; N, nucleus; P, porta-somes; PMM, perimicrovillar membranes; V, vesicles. 10 March 2021 www. hbmahesh. weebly. com 8
Protease 10 March 2021 www. hbmahesh. weebly. com 9
Amylase 10 March 2021 www. hbmahesh. weebly. com 10
Lipase 10 March 2021 www. hbmahesh. weebly. com 11
- Slides: 11